In vitro lifetime measurements were made of Nile Blue A (NBA) in EtOH, saline + albumin, cells, and cells after 24 hours to allow for the formation of metabolites. In vivo measurements included subcutaneous squamous carcinoma tumors and normal skin on nude mice give 25 mg/kg NBA ip. Autofluorescence from mice given no dye was measured. The fluorescence lifetime @ 655 in EtOH was 0.156 nsec when excited @ 630 nm. In the presence of albumin, which can bind the NBA in hydrophobic pockets, the lifetimes was increased to double exponentials of 1.1 and 5.7 nsec. Squamous carcinoma exposed to dye for several hours was similar to that of albumine-dye adduct. In nude mice given NBA, tumor average lifetime was 1.6 ns when excited @ 623 nm and detected @ 655 nm. Skin had similar lifetime decay. In this experiment, NIR Raman spectroscopy technique will be used to selectively detect the presence of subcutaneous tumors by identifying the presence of cationic dyes molecules.